The invention relates to a hot-gas engine.
A hot-gas engine of the type mentioned is known from DE 25 22 711 A1. The known engine, a Stirling cycle engine, comprises a cylinder in which a working piston, which is connected to a crank drive, is arranged so as to move to and fro in relation to a displacement piston, which is connected to the same drive. The displacement piston divides the cylinder space into a first working space, delimited by the cylinder cover, and a second working space, delimited by the working piston. The working spaces are connected to an external connection channel by way of a passage each which is provided in the cylinder wall, with said external connection channel comprising a heating device for heating up the working medium in the first working space, and a cooling device for cooling the working medium in the second working space, as well as a regenerator which is arranged between the heating device and the cooling device.
In order to obtain optimal yield of the heat conveyed, expressed in terms of thermal efficiency, generally speaking one tends to try to achieve as large a difference as possible between the temperatures of the working medium in the hot first working space and in the cold second working space. There is a disadvantage in that, in conventional hot-gas engines of the type mentioned, corresponding temperature differences occur also within the cylinder wall and within the walls of the heat-transmitting components, which temperature differences cause serious alternating thermal loads of these components, and can thus significantly shorten the service life of such components. In such designs, a limited temperature difference, which is matched to the permissible load of these components, and thus a corresponding limitation of the achievable thermal efficiency has to be accepted.